Certificate of correction



Dec. 10, 1957 H w DOU LASS APPARATUS FOR SHUTTfNG DOWN ENGINES 0NOCCURRENCE OF CERTAIN FAILURES Filed Dec. 8, 1955 OXI- DANT INVENIORHOWARD m DOUGLASS ATTORNEYS United States Patent APPARATUS FOR SHUTTINGDOWN ENGINES 0N OCCURRENCE OF CERTAIN FAILURES Howard W. Douglass,Berea, Ohio Application December 8, 1955, Serial No. 551,963

10 Claims. (Cl. 169-2) (Granted under Title 35, U. S. Code (1952), see.266) The invention described herein may be manufactured and used by orfor the Government of the United States of America for governmentalpurposes without the payment of any royalties thereon or therefor.

The present invention relates to an apparatus and system for shuttingdown engines when certain types of failures occur therein and forprotecting such engines against damage incidental to such failures. Moreparticularly the invention relates to an apparatus and system forshutting down immediately and for protecting from damage jet propulsionengines on occurrence of certain failures therein or in any of theelements contained therein.

In testing jet propulsion engines, particularly those using high-energypropellants, frequent burn-outs occur which result in seriousdestruction of test equipment. These burn-outs are difficult to avoid inthe experimental development of engines for which the demand is for everincreasing performance. Under such conditions failure of parts becauseof excessive stress, high pressures and excessive heat are commonoccurrences.

Heretofore, when burn-outs occurred in such engines, the damage rapidlyadvanced to complete destruction of the engine before an operator coulddetect the failure and close the valves necessary to shut otf the fueland oxidant supply to stop the engine, and operate fire extinguishingequipment.

An object of the present invention is to provide a new and improvedsystem for closing down an engine which is simple in operation.

Another object is to provide a new and improved system for shutting downa jet propulsion engine which is operated quickly and reliably when afailure occurs.

Still another object is to provide a new and improved system forprotecting a jet propulsion engine from substantial damage on failure ofcertain elements thereof.

Other objects and many of the attendant advantages of this inventionwill be readily appreciated as the same becomes better understood byreference to the following detailed description when considered inconnection with the accompanying drawings wherein:

Fig. l is an electrical diagram showing an embodiment of the system ofthe present invention;

Fig. 2 is a view in elevation of a portion of an engine and showing theburnout wire used with the present invention; and

Fig. 3 is an enlarged view in elevation of a portion of Fig. 2 andshowing the wire severed by a burnout or failure of an element.

Referring more particularly to the drawings, wherein like numeralsindicate like parts throughout the several views, the diagram of Fig. 1shows a typical circuit, suitable for the purpose wherein a pair ofconductors 10 and 11 are connected to a source of alternating current.The primary winding 12 ofa step-down transformer 13 is connected toconductors 10 and 11. The secondary winding 14 has a low voltage outputsuch, for example, as 6 volts A. C. A conductor 15 connects one side ofsecondary winding 14 to a burnout wire 16, an electric fuse 17 beingPatented Dec. 10, 1957 "ice interposed in conductor 15, betweensecondary winding 14 and burnout wire 16. The other side of burnout wire16 is connected to the winding 18 of a relay 19. Winding 18 is connectedto the other side of a secondary winding 14 through a conductor 22 and asecond fuse 23. A pilot lamp 21 is also connected between burnout wire16 and the secondary winding 14 of transformer 13 by means of conductor22 through conductor 10 in order to indicate when the low voltagecircuit is energized.

The burnout wire 16 may be any suitable insulated wire which will burnaway or break when an engine failure occurs, thus opening the lowvoltage circuit. Fuses 17 and 23 will open the circuit in the event thatthe insulation of wire 16 melts, grounding the circuit, but the wirefails to break.

Relay 19 is provided with a pair of switch arms 24 and 25. Arm 24 isnormally closed when the relay 19 is deenergized, while switch arm 25 isnormally open, under the same condition. When coil 18 of the relay 19 isenergized, arm 24 breaks a circuit through a contact 26, while arm 25closes a circuit through a contact 27 and a conductor 11a.

The circuit for contact 26 and arm 24 comprises a manual switch 28connected between arm 24 and condoctor 11, and a fire protection system29 connected between conductor 10 and contact 26. System 29 may includea source of carbon dioxide or other suitable fire extinguishing materialand a solenoid operated valve (not shown) for maintaining the system inshut-off condition until a break occurs in the low voltage circuit. Apilot light 30 is connected between contact 26 and conductor 10.

Arm 25 of the relay 19 controls the flow of volt current from conductor11 to a fuel shut-ofi valve 31 and an oxidant shut-off valve 32. Thesolenoid operated fuel valve 31 is connected to conductor 11a through amanual switch 33 while the other side is connected to conductor 10. Apilot light 34 is connected between switch 33 and conductor 10 toindicate when the fuel valve circuit is energized.

The solenoid operated oxidant valve 32 is connected to conductor 11athrough manual switch 35 and to conductor 10 on the other side thereof.A pilot light 36 is connected between switch 35 and conductor 10 toindicate when the oxidant valve circuit is energized.

It is, of course, understood that other electrically controlled meansmay also be connected between conductors 10 and 11a in the manner of thevalves 31 and 32 and controlled by switch arm 25 of relay 19.

As shown in Figs. 2 and 3, the burnout wire 16 may be taped to variousdanger points of the engine or the accessories thereof indicated at 37.A pair of conduits 38 and 39 which may be fuel or oxidant supply lines,are shown leading into the device 37 and wire 16 is shown taped theretoas at 41. The wire 16 may be looped back on itself to provide outgoingand return leads 42 and 43 at each danger point. The wire 16 may be ledfrom the circuit of Fig. l to each danger point in succession and backto the circuit. The wire 16 may also be wrapped around and taped to theentire casing of the engine or casings of accessories attached thereto,as shown at 44.

Fig. 3 shows a failure of conduit 39 in which a hole 40 has been causedby excessive pressure therein or by the melting of metal because of highheat and permitting the leakage of fuel or oxidant therethrough. Lead 42of wire 16 has been severed either by heat, fire, or explosive force,thus breaking the low voltage circuit passing therethrough. It is clearthat wire 16 will break at any point of failure protected thereby. It isalso to be noted that the single looped wire 16 comprising outgoing andreturn leads 42 and 43 may be trained over and secured to the variousparts of the engine to protect the entire engine 3 against fire andother damage as the result of failure of any part thereof.

In operation, the conductors l and 11 are connected to a suitable sourceof alternating current, such for example as 120 volts, and the manualswitches 28, 33 and 35 are closed. Normally closed switch arm 24 ismoved to the open position by relay winding 18, while normally openswitch arm is moved to the closed position by winding 18. Under thiscondition, the fire protection valve 29 is in closed position, whilefuel valve 31 and oxidant valve 32 are open, thus permitting operationof the engine.

When a failure develops in the engine or the components thereof,protected by the system of the present invention, burnout wire 16 breaksor burns out in the area of failure. The low voltage circuit isdeenergized by the breaking of wire 16 and winding 18 is alsodeenergized. Switch arms 24 and 25 are released by coil 18 to the normalpositions thereof, i. e., the closed position for 24 and the openposition for 25. In. the foregoing position. arm 24 provides current tocontact 26 thus energizing solenoid valve 29 to open. On opening valve29, carbon dioxide or other fire extinguishing material is sprayed orotherwise applied to the engine thus extinguishing or preventing anyfire caused by the failure.

Simultaneously with the closing of valve 2), switch arm 25 moves to theopen position, thus opening the fuel valve and oxidant valve circuits.Fuel valve 31 and oxidant valve 32 close when the solenoids thereof aredeenergized by opening of the circuits thereof. When valves 31 and 32are closed, the fuel and oxidant supplies to the engine are shut off,thus stopping the engine and prevent ing further fire being caused bythe fuel and oxidant.

From the foregoing, it is clear that there has been provided aprotective system for jet propelled engines which prevents damage tosuch engines due to failures in the engine mechanism, fuel and oxidantconduits, or other components thereof. While the circuit has beendescribed as being energized by 120 volts A. C., it may be adapted toother voltages where line voltage is not available, such as in anaircraft in flight.

Obviously many modifications and variations of the present invention arepossible in the light of the above teachings. It is therefore to beunderstood that within the scope of the appended claims the inventionmay be practiced otherwise than as specifically described.

What is claimed is:

l. A system for protecting jet propulsion engines from damage due tofailures in danger points comprising, a source of electrical power,means for reducing the voltage of said power source, a low voltagecircuit energized by said voltage reducing means, a higher voltagecircuit energized directly by said power source, a relay coil connectedin said low voltage circuit, a first switch normally biased to a closedposition in said higher voltage circuit and movable to an open positionby said relay coil when said coil is energized, a second switch normallybiased to an open position in said higher voltage circuit and movable toa closed position by said relay coil when said coil is energized, afirst solenoid operated valve connected to said first switch, said firstvalve being normally closed and energized to an open position when saidrelay coil is deenergized, a plurality of solenoid operated valves heldin an open position by said second switch when said relay coil isenergized and biased to a closed position when said relay coil isdeenergized, and a burnout wire in said low voltage circuit positionedadjacent at least one danger point in said engine whereby said wire willbe severed when a failure develops in the area of said danger pointthereby to deenergize said low voltage circuit and said coil.

2. A system for protecting jet propulsion engines from damage due tofailures in danger points comprising, a low voltage circuit, a highervoltage circuit, a relay coil connected in said low voltage circuit, anormally closed switch in said higher voltage circuit and movable to anopen position when said coil is energized, a normally open switch insaid higher voltage circuit and movable to a closed position when saidcoil is energized, a normally closed solenoid operated valve connectedto said normally closed switch and movable to an open position when saidrelay coil is deenergized, a plurality of normally open solenoid valvesmovable to a closed position when said normally open switch is releasedto an open position as said relay coil is deenergized, and a burnoutwire in said low voltage circuit positioned adjacent at least one dangerpoint in said engine whereby said wire will be severed when a failuredevelops in the area of said danger point thereby to deenergize said lowvoltage circuit and said coil.

3. A system for protecting jet propulsion engines from damage due tofailures in danger points comprising, a low voltage circuit, a highervoltage circuit. a relay having a coil, a normally open switch and anormally closed switch each connected in said higher voltage circuit,said coil being connected in said low voltage circuit whereby saidnormally open and normally closed switches are moved to the closed andopen positions respectively by said coil when said low voltage circuitis energized, a normally open solenoid operated valve held closed bysaid normally closed switch and movable to open position when energizedby the opening of said normally closed switch, and a normally closedvalve held in open position by said normally open switch when closed andreleasable to closed position when said normally open switch isreleased, and a burnout wire in said low voltage circuit positionedadjacent at least one danger point in said engine whereby said wire willbe severed when a failure develops in the area of said danger pointthereby to deenergize said low voltage circuit and said coil to releasesaid switches to the normal positions thereof.

4. A system for protecting jet propulsion engines from damage due tofailures in danger points comprising; a low voltage circuit having arelay coil therein, severable means in said low voltage circuit foropening said circuit when a failure develops in the area of said dangerpoint, said means positioned adjacent at least one danger point in saidengine, a higher voltage circuit, first circuit closing means in saidhigher voltage circuit held open when said relay coil is energized,second circuit closing means in said higher voltage circuit held closedwhen said relay coil is energized, first protection means connected tosaid first circuit closing means and activated when said low voltagecircuit is opened, fuel shut-off means connected to said second circuitclosing means and activated to shut off said fuel when said secondcircuit closing means is opened by the opening of said low voltagecircuit.

5. Apparatus for protecting jet propulsion engines from damage due tofailures in danger points comprising, means for activating a fireextinguishing system, means for shutting ofi the fuel and oxidant supplyto said engine, and failure sensing means comprising an electricalsystem including a burnout wire positioned adjacent at least one dangerpoint in said engine for activating said fire extinguishing systemactivating means and said fuel and oxidant shut-off means when a failuredevelops in said engine which severs said wire.

6. Apparatus for protecting jet propulsion engines from damage due tofailures in danger points comprising, first solenoid operated valvemeans for activating a fire extinguisher system, second solenoidoperated valve means for shutting off the fuel and oxidant supplies tosaid engine, and severable means positioned adjacent at least one dangerpoint in said engine for causing operation of said valve means when afailure develops in the area of said danger point.

7. Apparatus for protecting jet propulsion engines from damage due tofailures in danger points comprising, a first solenoid operated valve ina fire extinguisher system, a second solenoid operated valve forshutting off the fuel supply to said engine, a third solenoid operatedvalve for shutting off the oxidant supply to said engine, and failuresensing means comprising an electrical system including a burnout wirepositioned adjacent at least one danger point for activating said first,second, and third valves when a failure develops in said engine.

8. Apparatus for protecting jet propulsion engines from damage due tofailures in danger points comprising, a plurality of solenoid operatedvalves, means comprising an electrical system including a burnout wirepositioned adjacent at least one danger point for sensing a failure insaid engine, and circuit means initiated by said sensing means tooperate said plurality of valves.

9. Apparatus for protecting jet propulsion engines from damage due tofailures in danger points comprising, a plurality of damage preventionmeans, means comprising an electrical system including a burnout wirepositioned adjacent at least one danger point for sensing a failure insaid engine, and circuit means initiated by said sensing means tooperate said plurality of damage prevention means.

10. A system for protecting jet propulsion engines from damage due tofailures in danger points comprising, a source of electrical power,means for reducing the voltage of said power source, a low voltagecircuit energized by said voltage reducing means, a higher voltagecircuit energized directly by said power source, a relay coil connectedin said low voltage circuit, a first switch normally biased to a closedposition in said higher voltage circuit and movable to an open positionby said relay coil when said coil is energized, a second switch normallybiased to an open position in said higher voltage circuit and movable toa closed position by said relay coil when said coil is energizcd, afirst solenoid operated valve connected to said first switch, said firstvalve being normally closed and energized to an open position when saidrelay coil is deenergized, a plurality of solenoid operated valves heldin an open position by said second switch when said relay coil isenergized and biased to a closed position when said relay coil isdeenergized, an insulated burnout wire in said low voltage circuitpositioned adjacent at least one danger point in said engine wherebysaid wire will burn out when a failure develops in the area of saiddanger point to thereby deenergize said coil, and fuse means in said lowvoltage circuit operable to interrupt said circuit and deenergize saidcoil in the event that the insulation of said wire melts, grounding thecircuit but the wire does not break.

References Cited in the file of this patent UNITED STATES PATENTS1,840,986 Townsend Jan. 12, 1932 2,566,235 Mathisen Aug. 28, 19512,573,335 Hodgins et al Oct. 30, 1951 2,737,249 Pinkel et a1 Mar. 6,1956

